Facies & Fluids Probabilities

Estimate rock and fluid probabilities from inversions

Facies & Fluids Probabilities (FFP) is an interactive interpretation tool for determining lithofacies from the outcomes of acoustic and elastic inversions. Facies are usually defined in the petrophysical domain, after which proxies are confirmed in the elastic domain. Typically, P-impedance and Vp/Vs are used. For unconventional scenarios, the key elastic proxies could be geomechanical.

Bayesian estimation of the probabilities of occurrence of faciesBayesian inference can be used to infer the probabilities of occurrence of geologic facies from seismic reflection data. The input probability distributions come from observations from well logs, analogs, or models of the distributions of values for reservoir properties of interest. Reservoir properties can be defined by facies, lithologies, fluids, or any combination of these. It is simply required that the disparate facies be somewhat separable with respect to the properties derived from inversions.

The models are manifest as histograms which are subsequently modeled as Probability Density Functions (PDFs). Using an estimate of the uncertainty in the reservoir parameters from inversion, likelihoods are computed from the PDFs for each facies and at each voxel. From these, Bayesian estimates for the posterior probability of each facies/fluid are determined. In this way, facies-fluid probability volumes for each facies can be formed and a most-probable facies volume constructed.

The Jason advantage

• Optimize reservoir appraisal and assessment with probability-based QI interpretations

• Generate facies maps that are meaningful to geologists

• Discover unknown facies

The PDFs in the FFP design are user-editable from a dedicated GUI, making Facies & Fluids Probabilities (FFP) a useful interpretation tool.

Probability volumes for each lithotype are created by FFP.

Most-likely lithotype at each sample is calculated from FFP probability volumes.

Key features• Bayesian-based facies interpretation

• Templates from logs and analogues

• Inputs are Jason inversions

• Probability volumes for all Facies

• Most-probable Facies volumes

• Uncertainty estimates and bias corrections

• Log QC available

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Facies & Fluid Probabilities

Operating system requirementsThe following operating systems and graphic systems are supported

• Linux™ Red Hat® Enterprise 4,5 or 6

• Linux™ SUSE™ 11.x, Enterprise (SLES10)

• Windows® (32 & 64 bit) – XP SP3, Vista™,Windows® 7

• Requires Nvidia® graphics

Interoperability

• Jason RockTrace®

• Jason InverTrace® Plus

Designing Facies PDFs in P Impedance – Vp/Vs space.

Identify most-likely pay distribution.

Jason

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